JSONFlattener
Flattens JSON (JavaScript Object Notation) objects, extracting the object keys and values into FME feature attributes.
For example, consider a feature which has an attribute named json containing the following text:
{ "paramName":"GeocodeResult", "dataType":"GPFeatureRecordSetLayer", "value": { "geometryType":"esriGeometryPoint", "spatialReference": {"wkid":4326 } } }
After going through the JSONFlattener, the following attributes will have been added to the feature:
Attribute Name | Attribute Value |
---|---|
paramName | GeocodeResult |
dataType | GPFeatureRecordSetLayer |
value.geometryType | esriGeometryPoint |
value.spatialReference.wkid | 4326 |
Output Ports
Features which are successfully processed will be output through this port.
Features which could not be successfully processed will be output through this port. Typically this happens when the attribute specified in the JSON Attribute parameter does not have a value, or has a value that is not valid JSON.
Parameters
Source
Allows for selecting between one of two options for JSON input: JSON Document or File/URL
If selected, The JSON document can come from any string expression, including attribute values and workspace parameters.
If selected, the JSON source can be read from a local file at a specified file path, or from the internet at a specified URL.
Flattening Parameters
If this parameter is set to No, each JSON object key will become an attribute and the corresponding JSON value will become the attribute value. If this parameter is set to Yes, only object values which are simple types (integers, strings, etc) will become attribute values, while nested objects and arrays will be recursively flattened, as shown in the above example.
This parameter may be used to provide a string with which to prefix the newly-created attributes.
Exposes any attributes so they can be used by other transformers. Type directly in the text box or click the browse button to display the editor and add attributes there.
Error Handling Parameters
Name of the list attribute that contains information on JSON validation errors. The features that exit the transformer through the <Rejected> output port will have validation errors listed in this list attribute. Each validation error message is made up of four parts:
- Error description
- Line number where the error occurred
- Column number where the error occurred
- Error type/severity
Note: List attributes are not accessible from the output schema in Workbench unless they are first processed using a transformer that operates on them, such as ListExploder or ListConcatenator. Alternatively, AttributeExposer can be used.
FME Licensing Level
FME Professional edition and above
Editing Transformer Parameters
Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.
Defining Values
There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.
Using the Text Editor
The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.
Using the Arithmetic Editor
The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.
Conditional Values
Set values depending on one or more test conditions that either pass or fail.
Parameter Condition Definition Dialog
Content
Expressions and strings can include a number of functions, characters, parameters, and more.
When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.
These functions manipulate and format strings. | |
Special Characters |
A set of control characters is available in the Text Editor. |
Math functions are available in both editors. | |
Date/Time Functions | Date and time functions are available in the Text Editor. |
These operators are available in the Arithmetic Editor. | |
These return primarily feature-specific values. | |
FME and workspace-specific parameters may be used. | |
Creating and Modifying User Parameters | Create your own editable parameters. |
Dialog Options - Tables
Transformers with table-style parameters have additional tools for populating and manipulating values.
Row Reordering
|
Enabled once you have clicked on a row item. Choices include:
|
Cut, Copy, and Paste
|
Enabled once you have clicked on a row item. Choices include:
Cut, copy, and paste may be used within a transformer, or between transformers. |
Filter
|
Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output. |
Import
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Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers. |
Reset/Refresh
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Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers. |
Note: Not all tools are available in all transformers.
FME Community
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Search for samples and information about this transformer on the FME Community.